One Tiny Word
by Comana
Summary: In the Episode the End, we get to know that Sam said yes to Lucifer in the future. But what could the Devil possibly have done to Sam that would shatter his resolve? It begins with the Devil finding Sam before Sam can find him.
Summary: In the Episode the End (5x04), we get to know that Sam said yes to Lucifer in the future. But what could the Devil possibly have done to Sam that would shatter his resolve? It begins with the Devil finding Sam before Sam can find him. Dark. Endverse.

Rated T for swearing and mentions of violence.

Disclaimer: All these characters aren't mine and Supernatural isn't mine either.

AN: Ok, this story will be another dark one, it's full of angst and desperation and I'm already sorry for it, but I had to find a good explanation to Sam saying Yes… and if it's any consolation, it never happened that way because Dean changed the future.

 **One Tiny Word**

It had been just another day on the road, and god was Sam tired. When he found the next shady motel on the side of the road he was happy that he could finally stretch his legs out on a bed. Well, maybe not happy but relieved. He didn't feel happy anymore. Not since that life-changing phone call six months ago. He had been utterly desperate after Lucifer told him that he was his destined vessel, and Dean shoving him away after that revelation was even worse. Dean had been his safe harbour – Sam unconsciously shook his head. _Don't think about that, think about your task_. Sam sighed and thought back to the last demon he exorcised. Before he had told him the whereabouts of another demon, one he was sure knew where Lucifer was. Sam doubted it, the demon had been desperate, and he did hunt for the Devil for six months now and he had found jack shit. Sam was certain that only some of his most trusted demons knew where Lucifer actually was. And he was good at covering his tracks. After the Croatoan virus was set free, Sam thought it might be easy to find him where it started, in San Francisco, but there was no sign of him, not even a trace of demons. He had been already gone.

Instead zombies everywhere. Sam barely escaped the city before it was shut down and fenced. The virus had spread ever since. Not as fast as Sam feared, but more and more cities on the west coast had to be enclosed and there were strict controls to prevent dispersion. However, it still spread and over time, Sam began to fear that even if he might be able to kill the Devil, that humanity would die anyway because of the virus.  
With this heavy weight in his stomach, Sam let himself fall onto the ugly green bed, that fit just perfectly to the ugly brown walls and the ugly grey plastic chairs of the motel. Like every night he asked himself why he was still able to sleep that well, but he long ago concluded that it was because he was just functioning. Like when Dean had been in hell. He was like a machine, doing what he had to do, and nothing else. Because there was nothing else he had. And there wouldn't be anything until he found the Devil and sent him back to where he belonged. He would right out his mistake or die trying, and if he somehow survived that – and that was a big if, by the way – he might get back to the life he had before, maybe even reach out to his brother… _No, stop thinking about that, think about your task_.  
Sam sighed once more and slid his arms around the pillow, thinking of the demon he would go after tommorow, in Detroit, and slowly fell into sleep.

Sam awoke early in the morning, like always. He packed his few things together and quickly checked out. On the way to the house where he would find the demon, Sam thought about his other problem. The one he had yet no solution for. Because if somewhere along the way, one of the demons knew where Lucifer was, Sam had no idea how to kill him. He could try to use the Demon knife, it might even work, after all the Devil was the father of the demonic race. But Sam would feel a lot better if he was sure that it would work, or if he had another effective weapon. He had already thought of the colt and made a few calls, but as far as the people he asked knew, the colt had vanished or had been fused in.

Maybe if he finally found a demon higher up in the food chain, it might know something about how to kill the Devil.

Sam stopped the car a few houses away from the address he'd gotten. The house was in a peaceful neighbourhood full of one-family houses in Detroit.

There were no people in front of the house he aimed for. This could be a good or a bad sign. Good that it wasn't heavily guarded, and bad if the demon had set him up.

Sam stashed his pockets with holy water, salt, Ruby's knife and his gun for good measure and walked to the front door. He picked the lock in two seconds and was immediately overwhelmed by the reek of rotting flesh. He couldn't see a cause yet, but he had seen enough demon-occupied households to know that the surplus family members that excelled the number of demons and couldn't be used as meatsuits were often killed.

Sam heard some shuffling upstairs and slowly climbed the wooden stairs. Through an open door, he could see a dining room and heard two male voices talking. He approached the door until he could see two dark-haired men, standing before the table and quietly talking to each other. Sam just wanted to make his move when he heard a third voice.

"Sam, stop loitering at the door, come in."

This voice was much louder, addressed at him and – to his utter horror - more familiar. _No! All but that!_

The two men now also looked at him, and all Sam wanted to do was run. But he wouldn't. He would go in and finish his task somehow.

He cautiously stepped inside the room, and could finally see the third man. He had been obscured by the door before. He was leaning comfortably against the kitchen counter that connected openly to the dining room. Sam had been warned by the voice, but seeing Lucifer in person made his resolve crumble. An ice cold fear clenched in his gut and spread through his whole body. How could he possibly have found him? He had the enochian on his ribs, hadn't he? But here Lucifer stood, without a care in the world.

Sam stood his ground, keeping the door close by and while looking at the Devil, he still kept track of the two in all likelihood demons.

The blond man looked Sam up and down, and Sam saw some splotches of missing skin in his face. They hadn't been there when he appeared in his dreams, but maybe the Devil really had a narcissistic streak.

"Yes, my vessel is slowly falling apart, Sam," he must have seen Sam's glances, "that's why I need you. You are my true vessel, you won't fall apart like Nick here."

Sam shoved the despair that he felt, away. This situation was a total mess, and he might die here, but he could also make the best of it and try to kill the abomination still leaning cosily at the kitchen counter.

"Is that why you're here? How did you know I'd come?"

Lucifer huffed. "That was not hard, Sammy," and Sam's skin crawled at the carelessly spoken nickname, "I had some demons track you, and as soon as they had your lead, it was easy to find a demon to give you this location."

Sam gave the two demons another look, and the Devil saw it. "Leave us, I'll handle this myself."

And they disappeared. Sam didn't know if he should feel relieved because there were fewer opponents or offended because the Devil obviously didn't rate him enough of a threat.

"So, let me explain to you why I arranged this meeting."

He pushed himself lightly off the counter and strolled towards Sam. Sam could only watch him closely, ready to counter every dirty move he would make.

"Sam, Sam, Sam. I'm not here to fight you. Relax. I'm actually only here to ask you to say Yes. One last time."

Sam stiffened. That wasn't what he expected, and he didn't trust him enough to believe him. Hell, the creature before him was the Devil, if there was something like negative trust, that's what it deserved.

"You don't believe me, Sam. But that's ok, I will show you that I don't lie."

He came even closer, and Sam shifted his right arm so that he could reach Ruby's knife that he had stowed in his sleeve. This was his chance, and he would use it.

As Lucifer made his next step, Sam also made a step forward, and lashed his hand with the dagger at Lucifer, with extra momentum from a turn of his upper body.

Lucifer was quick. Too quick for Sam. He had his hands up and ready to block Sam, but in the last moment, he let them sink again, and the dagger embedded itself deeply in his chest. Sam's eyes were glued on the dagger and the red blood slowly seeping around it, he was breathing heavily, and his white-knuckled hand couldn't let go of the hilt. He slowly looked up, and strangely the major emotion in the Devil's disintegrating face was disappointment.

With a startled exhale, Sam let go and stepped back. The man before him shot an annoyed glance at his chest, pulled the dagger out and threw it into a corner.

"This won't harm me, Sam. You seem to forget, like most people I have to say, that I am still an angel." The wound vanished together with the blood. It was as if Sam's attack never happened.

"I know Sammy. You have planned to find me later, and till then, you wanted to have found a weapon to kill me. But trust me, Sam. There is no weapon able to kill me that you could have possibly gotten your hands on, not in six months, and not in ten years."

Sam couldn't suppress a shiver. His knife was gone, his gun wouldn't use anything, and he had no chance to win in a fight. He glanced at the door, but that was just wishful thinking. How could he possibly run away from an angel that powerful. He pushed his fear – and it was no small amount – down. "What do you want?"

"Like I said, I just want to ask you to say Yes."

"Well, okay, my answer is No, can I go now?"

Sam knew that it wouldn't be that easy, but he had long ago exceeded the state of desperate. After all, he was standing in a room with the Devil himself, who wanted to possess him. If one was allowed a hue of panic, this was the convenient situation.

"Not yet, I just want to make sure that you know all the consequences if you keep denying me. And I promise, you won't like those consequences."

That really didn't sound good. He would never say Yes, he wouldn't condemn every person on the planet to the Devil, but in the moment Sam had no other choice than to play the game. "Ok, what are the consequences?"

The Devil shot him a smile and grabbed his arm faster than Sam could react. He felt the cold hand and after that a familiar pull in his gut and a slight nausea, the typical signs of the fast angel transportation. He looked around and found himself next to Lucifer, standing in a small hut. It was empty and smelled of mouldered wood. The single window was murky from years of neglect. Outside were some trees, and Sam could make out some more huts. And people walking in between.

A group of four people was just passing the path a dozen meters from the house. Sam could make out a gruff ordering voice that was just too familiar. That tone had so often been addressed at him that he couldn't possibly mistake it. His gut constricted even more and when he could finally allocate one of the blurry persons, with the determined but slightly bow-legged walk, he couldn't suppress a desperate breath of "Dean."

The Devil, who had closely watched Sam, now chimed in. "Yeah, it's your brother, just over there. How long haven't you seen him, Sam? Six months? I can assure you, you are not the only one who is practically dead inside, I guess it lies in the family."

Lucifer sounded conversationally, but Sam realized that him being here could only mean something very bad for Dean. Sam had to desperately gather his thoughts, because seeing his big brother, the one he hadn't spoken to in six months, who he had shoved from his thoughts every time he had grazed them, it was emotional. But he had to focus on the here and now, namely the Devil being in close proximity of both him and Dean. Thank God, in the moment Lucifer seemed to be contended with watching the group outside the window.

Sam had to warn them. And there was the slight chance that Dean had found a way to kill an archangel like Lucifer.

Sam leapt to the door, a shout on his lips, but Lucifer was faster than any human could be. He slammed into Sam with all his weight and crammed him against the door, one hand covering Sam's mouth and muffling his scream.

The air went out of Sam's lungs anyway with the impact, and he found himself in a position with Lucifer much too close for comfort. He was nearly at eye level with him and looked slightly angered. That couldn't be good. It was a bit strange, but Sam had never seen him angry before.

"Sam. I brought you here to show you something. Not to interfere." He fixated Sam with his blue eyes, and since Sam didn't answer because of the cold hand that was still firmly pressed on his mouth, he continued. "I just wanted you to realize that I know where your brother is. I've known it for quite some time now, but he is no threat and he can keep his small camp for the time being." He paused a moment, looking into the air as if expecting to see something there, before he fixated back on Sam. "As long as you say Yes. See, if you say No, I will get this little brother of yours and keep him for…entertainment. Well, mine, certainly not his."

He ended with a small humourless laugh and Sam internally froze but simultaneously was on fire. He breathed heavily when he began to realize what the Devil just told him. If Sam continued to say No, Dean would be condemned to endless torture by the abomination before him. Dean, who had just made it out of hell – into which he came in the first place because of Sam. He would have to endure it all over again. Sam shivered, and not just from the cold that emanated from the Devil's body that still crowded him against the wall. He wanted to say something, he didn't know what, but anything to end this awful fear-drenched silence. Lucifer noticed, and Sam felt another pull deep in his gut and they were back in the dining room in Detroit from earlier. Sam had no wall behind him and fell to the floor hard. Lucifer just stood and watched him like an insect that did something interesting.

"Why do you do this?" Not very original, but Sam felt more than a bit overwhelmed by the whole situation. In the morning, he had planned to interrogate a demon, and now Lucifer wanted to coerce him to consent. Things got sour astonishingly quick.

"Sam," Sam wanted to club that fake sympathetic look out of his face, "I won't lie to you, my vessel is breaking down, Nick will just hold me for three more months, and I have to look for other strategies if you keep saying No. Therefore the ultimatum, Sam. Today will be your last chance to say Yes, otherwise I will go for plan B, which among other things involves your brother becoming my chewing toy. Well, that's not a big part of my plan, but it will be my method to castigate you. One might think that Dean, with his time being in hell, is used to torture, but let me assure you, the things I will put him through won't be equal to anything he has experienced yet. And if my vessel breaks, I will drag him to hell with me. He will stay there, broken and as my pet, for eternity."

Sam, still awkwardly sitting on the floor, nearly retched at the thought of Dean having to endure this. So either he let the Devil in and condemned humanity or he denied the Devil and condemned Dean. _Fuck._

"The answer is still No," Sam was proud that his voice sounded relatively firm. He felt like he broke into pieces on the inside saying it. This was no real choice, he would put humanity first, as he knew Dean expected of him. If their roles were reversed, he'd want Dean to choose humanity, too, and he knew that he would.  
Maybe Sam could reach Dean and warn him before Lucifer came to grab him.

"Oh, Sam," his thoughts were once again interrupted by Lucifer, "I hadn't finished yet – with the consequences. I know that you'd put humanity before your brother, and I know that the both of you with your hero complex would sacrifice yourselves for the greater good, but there is just one problem." Lucifer went over to Sam and crouched down, clasping a hand onto his shoulder. Sam used his legs to shove himself away, but his back soon hit the wall, and Lucifer closed in on him. "You see, I was cast out of heaven because of you filthy apes, and if I can't stay on the surface of this earth, I will take the festering wound that humanity is with me. One last good deed you could say." The determined look, tainted with the slightest hint of disgust, told Sam that Lucifer meant it. He had no idea how he wanted to do it, kill all humans on earth, but he was hell-bent on doing it somehow. Lucifer, kneeling in front of Sam and surmounting him slightly, shifted a bit and produced a hand-long glass tube with Metal on both sides. It looked like from a cheap action movie and Sam got a strong idea on where this was going. He prayed that he was wrong, though.  
The Devil held the tube in front of Sam's face. In it was a murky white liquid.

"This is the Croatoan virus," and Sam's suspicion was affirmed – well, not completely.

"You already set the Croatoan virus free, what do you want with that?"

The Devil chuckled deeply, as if he wanted to delay a hilarious punch line. Sam more and more felt the urge to just rip his already decaying face off and be done with it.

"It is the Croatoan virus, but it's modified. Airborne."

All the colour left Sam's face, and Lucifer was visibly delighted. "I knew you'd like that plot twist, Sammy. You see, if I break this little tube, and I will if I don't find a new vessel, world's population will be erased in about two months. Maybe a bit longer in some remote areas. That means you have to rearrange your equation, Sam. If you say No, humanity dies, if you say yes, they'll survive."

Sam began to shiver. How could he possibly make such a decision? And why did it have to be him? Who had laid the fate of all people in his hands? He didn't want this. He didn't want to be walking around with Lucifer as his pilot, and he didn't want everybody to die.

He brought his too heavy breaths back under control. Lucifer was still watching him from slightly above, waiting for a response.

"And if I say Yes, you'll never release the virus? I'm a bit doubtful, since you already released the normal version of the Croatoan virus."

Lucifer raised his brows and his forehead creased.

"I know that you're suspicious, Sam. But you have to know what my goals are. I want humanity to be reborn. I will make you better. But you have overpopulated this planet greatly, and I will rebuilt humankind with the 0,2% of the people that will be left after the normal Croatoan virus is done with them."

0,2%, that was just awful. If not for the abomination kneeling before him, he might have cried at his hopeless situation. Save two thousandth of the human population or let them all die. The answer should be clear, but it wasn't. The problem was that it was Lucifer. Maybe all of these were just hollow threats to get him to say Yes, how could he possibly trust the Devil to say the truth?

"Oh, I know that look. You think I'm bluffing. But Sam, I never lied to you, and I never will," he shook his head, contemplated something and stood up. "I will give you five minutes to overthink it, but after that I need an answer."

Sam wanted to say something, ask something, get more information, but he stayed silent. If Lucifer left him alone, he could call Dean and… he didn't know what then, ask him what to do? Warn him? Or just have someone to talk –"

"Sorry for that, by the way," his thoughts were interrupted by Lucifer, "But I can't risk you escaping." And with that, he vanished into thin air.

What had he apologized for? Sam heard a series of eight sickening snaps before the pain made him slump down and whimper miserably. Waves of pain pulsed through the entirety of his legs, and he knew that they were broken multiple times. _Sick bastard_. Sam knew at least ten methods to prevent flight without making mush of someone's legs.

But he was finally alone and reached for his phone.

It was dead.

Completely dead. Just like Sam's mind when he stared at it. His last shiver of hope died down and panned out, just like that. Tears fell from his eyes, not of pain, but of despair and sheer helplessness. A first sob escaped his lips and he was a bit relieved that he was left alone for the moment. He could do very well without Lucifer witnessing his breakdown.

When the sobs died down, he was completely empty inside. He knew what he had to do. He had no other choice, and the Devil had made sure that he would make a choice and couldn't escape. There was really just one choice he could make, the one for humanity and Dean. But why did he feel so bad, then? If it was the right choice, shouldn't it at least feel a bit right? But the thought of giving his body over to Lucifer just made him sick to his bones. And the worst thing was, nobody would know why he said Yes. _No, correct that_ , Dean wouldn't know why Sam had said Yes, and he would be even more disappointed than after Sam started the Apocalypse.

Even worse, Dean would have to fight against Lucifer in his body, and Sam knew that that would break Dean. Maybe they'd both be lucky and Dean would just try to save some people and not go against the Devil. Fuck, who was he kidding, Dean would be in the front line against Lucifer. And Sam really couldn't criticize him for it.

Sam had no idea how much time had passed, but as he sat against the wall, his legs throbbing in pain, but not nearly hurting as much as he hurt inside, he could just think of the midday sun that filtered through the window, and how it really didn't fit with what was going on. The future of all people was on the line, hell, it should be lightning, raining and hailing. But the sun continued to shine and warmed his cold skin.

A shadow fell over him, and Lucifer had returned.

Before he could say something, Sam interjected. "If I say Yes, do you give me your word that you won't set that virus free and that you won't hurt Dean?"

Lucifer still stood before him, curiously looking down at Sam. "I do promise that I won't set the virus free, and I promise that I won't go after your brother. But, and that's a considerate but, if your brother threatens my life, I will kill him." Sam wanted to object, but he didn't find the words.

"Don't worry, he'll have a quick death and I won't drag him to hell or anything. He'll just be – dead."

That was maybe more than he could hope for. And a small rebellious part in Sam perked up and told him that the Devil shouldn't be so sure that he'd be able to kill Dean before Dean killed him.

"I want to speak to Dean one last time." His voice didn't waver, they were playing with the highest stakes and Sam really needed that talk, not just to warn Dean, but also to just explain.

"I can't do that, Sam. You know my plans, you could tell him and say No afterwards. That won't happen. I have you exactly where I want you, and I now need an answer," he made a small pause, "if it's any consolation, if I get the chance to do it, and your brother is dumb enough to attack me later, I will tell him why you chose this, before I kill him. It won't be much, but I guess he might be able to rest more in peace with that knowledge. Even though, and I want you to know that, Sam, you'll be never able to rest in peace. I will have your body for eternity and you'll be by my side."

That was not really a consolation, but it was all he would get. Sam couldn't suppress the tears when he looked up at Lucifer. The blond man smiled, knowing that he had played everything right. Sam took three more breaths, the last ones he would make while being his own master, and made the hardest and gravest decision of his life.

"Yes."

* * *

AN: I'm sorry that I couldn't give you a happy end, but it just didn't fit. Well, at least it never happened, so that's something, isn't it?  
Please review, I'm always happy to get some feedback and/or constructive criticism :)  
I'm also sorry for eventual spelling or grammar mistakes, English isn't my native language, so if you find some mistakes, I'd be happy to correct them ;)


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